Cleaning Module, Cleaning Apparatus and Method of Cleaning Photomask

ABSTRACT

In a method of cleaning a photomask, a wiper tape is guided from a wiper tape supplying reel, over a cleaning head, and then onto a wiper tape collecting reel. A section of the wiper tape over the cleaning head is brought into contact with an adhesive residue on a surface of the photomask. A relative movement is caused between the photomask and the section of the wiper tape to remove the adhesive residue from the surface of the photomask.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.15/857,751, filed on Dec. 29, 2017, entitled “Cleaning Module, CleaningApparatus and Method of Cleaning Photomask”, which is a divisional ofU.S. application Ser. No. 14/154,780, filed on Jan. 14, 2014, now U.S.Pat. No. 9,857,680 issued Jan. 2, 2018, entitled “Cleaning Module,Cleaning Apparatus and Method of Cleaning Photomask”, each applicationis hereby incorporated herein by reference.

BACKGROUND

Semiconductor manufacture involves numerous processes, includingdeposition, photolithography, etch and the like processes. In aphotolithography process, a photomask is used to pattern variousfeatures in semiconductor devices being manufactured. The cleanliness ofa photomask is a consideration concerning quality of the patternedfeatures and the semiconductor devices.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1A is a schematic cross-section view of a photomask in ade-pellicle process in accordance with some embodiments.

FIG. 1B is a schematic top view of a photomask after a de-pellicleprocess in accordance with some embodiments.

FIG. 2A is a schematic top-front-right perspective view of a cleaningapparatus in accordance with some embodiments.

FIG. 2B is a schematic left view of a cleaning apparatus m accordancewith some embodiments.

FIG. 3A is a schematic top-front-right perspective view of a cleaningmodule in accordance with some embodiments.

FIG. 3B is a schematic top-rear-right perspective view of a cleaningmodule in accordance with some embodiments.

FIG. 3C is a schematic rear view of one or more components of a cleaningmodule in accordance with some embodiments.

FIG. 3D is a schematic front view of one or more components of acleaning module in accordance with some embodiments.

FIG. 3E is a schematic, top-front-right perspective view of a portion ofa cleaning module in accordance with some embodiments.

FIG. 3F is a schematic perspective view of a wall of a case of acleaning module in accordance with some embodiments.

FIG. 3G is a schematic front view of one or more components in a portionof a cleaning module in accordance with some embodiments.

FIG. 4 is a schematic top-front-right perspective view of a cleaningmodule in accordance with some embodiments.

FIG. 5 is a schematic top-front-right perspective view of one or morecomponents of a cleaning module in accordance with some embodiments.

FIG. 6 is a schematic rear view of cleaning modules m a cleaningapparatus in accordance with some embodiments.

FIG. 7 is a schematic rear view of a cleaning module in a cleaningoperation in accordance with some embodiments.

FIG. 8 is a schematic block diagram of a cleaning apparatus inaccordance with some embodiments.

FIG. 9 is a flow chart of a method of cleaning a photomask in accordancewith some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact. In addition,the present disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

FIG. 1A is a schematic cross-section view of a photomask 100 in ade-pellicle process in accordance with some embodiments. To protect thephotomask 100 from contaminants, a pellicle 102 is mounted on thephotomask 100. In some embodiments, the pellicle 102 includes a frameand a transparent film stretched over and attached to one side of theframe. An opposite side of the frame is bonded to the photomask 100 byan adhesive 104. As a result, contaminants are deposited on the pellicle102, rather than on the photomask 100 which is spaced from the depositedcontaminants by a height of the frame. In a photolithography process,light is focused on the photomask 100 and the contaminants deposited onthe pellicle 102 are unlikely to affect the quality of patterns to beproduced. In some situations, the pellicle 102 is removed from thephotomask 100 to permit the photomask 100 to be cleaned or reworked.This process is referred to as a de-pellicle process. When the pellicle102 is removed from the photomask 100 in a de-pellicle process asindicated by arrow 105 in FIG. 1A, residue of the adhesive 104 remainson the photomask 100.

FIG. 1B is a schematic top view of the photomask 100 after a de-pellicleprocess in accordance with some embodiments. As indicated in FIG. 1 B,the residues of the adhesive 104 (hereinafter “adhesive residues”)remain on the photomask 100 in bonding regions where the frame of thepellicle 102 was bonded to the photomask 100, and the adhesive residueshave a shape of the frame of the pellicle 102. For example, the adhesiveresidues remain along the periphery of a rectangle having sides 106, 108extending in the X direction, and sides 107, 109 extending in the Ydirection, as shown in FIG. 1B. In some situations, the adhesiveresidues include intermittently arranged adhesive spots. In somesituations, the adhesive residues include portions outside the bondingregions.

To remove the adhesive residues to prepare the photomask for subsequentprocessing, some embodiments provide one or more cleaning modules,cleaning apparatuses and/or methods of cleaning photomasks. In someembodiments, the described cleaning modules, cleaning apparatuses and/ormethods are configured and/or used to remove substances other thanadhesive and/or to clean substrates other than photomasks.

FIG. 2A is a schematic top-front-right perspective view of a cleaningapparatus 200, and FIG. 2B is a schematic left view of the cleaningapparatus 200 in accordance with some embodiments. The cleaningapparatus 200 includes a housing 210 accommodating therein one or morecleaning modules 220, 230, a stage 240, at least one cleaning substancestorage 250, a controller 260, and a ventilation device 270.

The housing 210 is box-shaped and has a top wall 211, a bottom wall (notshown), a front wall 212, a rear wall 213, a right wall 214, and a leftwall 215. In one or more embodiments, the top wall 211, bottom wall,front wall 212, rear wall 213, right wall 214, and left wall 215 of thehousing 210 are hermetically coupled together to form a clean-roomenvironment inside the housing 210. At least one of the walls of thehousing 210 has a door arranged to permit an operator or equipment toaccess one or more components inside the housing 210. The housing 210 isdivided into an upper section 216 and a lower section 217. The uppersection 216 accommodates therein the cleaning modules 220, 230, and thestage 240. The upper section 216 includes a frame or rail arrangement218 adjacent the top wall 211. The cleaning modules 220, 230 are mountedon the frame or rail arrangement 218 to be suspended above the stage240. The lower section 217 includes a partition wall 219 dividing thelower section 217 into a left part adjacent the left wall 215 and aright part adjacent the right wall 214. The left part of the lowersection 217 accommodates the cleaning substance storage 250. The rightpart of the lower section 217 accommodates the controller 260. Thedescribed arrangement of the housing 210 is an example. Otherarrangements are within the scope of various embodiments.

The cleaning modules 220, 230 are arranged in the upper section 216 ofthe housing 210 and mounted on the frame or rail arrangement 218 to besuspended above the stage 240. In some embodiments, at least one of thecleaning modules 220, 230 is movable along the frame or rail arrangement218 to be positioned corresponding to a spot to be cleaned on asubstrate. In at least one embodiment, one of the cleaning modules 220,230 is configured to clean the substrate along a first line extending inthe first direction, whereas the other of the cleaning modules 220, 230is configured to clean the substrate along a second line extending inthe second direction transverse to the first direction. For example, thecleaning module 220 is arranged to clean the substrate along a lineextending in the Y direction. When a photomask such as the photomask 100shown in FIG. 1B is to be cleaned by the cleaning apparatus 200, thecleaning module 220 is arranged to remove adhesive residues along thesides 107, 109 which are oriented in the Y direction. Similarly, thecleaning module 230 is arranged to clean the substrate along a lineextending in the X direction. When a photomask such as the photomask 100shown in FIG. 1B is to be cleaned by the cleaning apparatus 200, thecleaning module 230 is arranged to remove adhesive residues along thesides 106, 108 which are oriented in the X direction. In someembodiments, the cleaning modules 220, 230 are configured tosimultaneously clean different lines at the same time. In someembodiments, the cleaning modules 220, 230 are identically configured.In at least one embodiment, one of the cleaning modules 220, 230 isomitted. In at least one embodiment, more than two cleaning modules areincluded in the cleaning apparatus 200.

The stage 240 is arranged in the upper section 216 of the housing 210.The stage 240 includes an X-stage 242 and a Y-stage 244. The X-stage 242has a substrate holder 246 configured to hold a substrate to be cleanedthereon. In at least one embodiment, the substrate is a photomask thatunderwent a de-pellicle process and has adhesive residues remainingthereon. The substrate holder 246 is configured to hold the substrate byvacuum, mechanical engagement, or the like arrangements. The X-stage 242is configured to move the substrate holder 246 with the substrate heldthereon in the X direction to cause a relative movement in the Xdirection between the substrate to be cleaned and one or more of thecleaning modules 220, 230. The Y-stage 244 is configured to move theX-stage 242 with the substrate held thereon in the Y direction to causea relative movement in the Y direction between the substrate to becleaned and one or more of the cleaning modules 220, 230. In at leastone embodiment, the stage 240 is further configured to cause a relativemovement in the Z direction between the substrate to be cleaned and oneor more of the cleaning modules 220, 230. The described arrangement ofthe stage 240 is an example. Other arrangements are within the scope ofvarious embodiments.

The cleaning substance storage 250 is arranged in the lower section 217of the housing 210. The cleaning substance storage 250 is configured tostore one or more cleaning substances. In at least one embodiment, theone or more cleaning substances include a solvent or solvents of thematerial to be removed from the substrate to be cleaned. In at least oneembodiment, more than two cleaning substances are stored in the cleaningsubstance storage 250. In at least one embodiment, the cleaningsubstance storage 250 is configured to dispense different cleaningsubstances at different stages to clean the same surface of thesubstrate. In some embodiments, the cleaning substance storage 250 iscoupled to at least one of the cleaning modules 220, 230 to supply oneor more cleaning substances to the cleaning module(s). In someembodiments, the cleaning substance storage 250 is coupled to a nozzlearranged at the stage 240 to dispense one or more cleaning substances onthe substrate. In at least one embodiment, the cleaning substancestorage 250 is omitted from the cleaning apparatus 200, and a cleaningsubstance is supplied, e.g., via piping, from an external storage intothe housing 210. The described arrangement of the cleaning substancestorage 250 is an example. Other arrangements are within the scope ofvarious embodiments.

The controller 260 includes a computer 262 and one or more applicationspecific integrated circuits (ASICs) 264. In some embodiments, thecomputer 262 includes at least one processor, a memory, a networkinterface, a storage device, an input/output (I/O) device or otherinterconnection communication mechanisms. The memory comprises, in someembodiments, a random access memory (RAM) and/or other dynamic storagedevice and/or read only memory (ROM) and/or other static storage device.The memory is used, in some embodiments, for storing temporary variablesor other intermediate information during execution of instructions to beexecuted by the processor. In some embodiments, the storage device, suchas a magnetic disk or optical disk, is configured to store data and/orinstructions. The 1/0 device comprises an input device, an output deviceand/or a combined input/output device for enabling user interaction. Forexample, a touch screen 266 is provided at the front wall 212 of thehousing 210 and configured as a user interface for 1/0 interaction withthe computer 262 and/or the ASIC 264. In another example, a camera (notshown) is provided in the upper section 216 of the housing 210 andfacing the stage 240 to capture and transmit one or more images of thesurface to the computer 262 and/or ASIC 264. The computer 262 and/orASIC 264 is configured to analyze the captured images to determine ifthe substrate has been cleaned, or another cleaning operation with thesame or different parameters is to be performed. Other types of 1/0devices, such as mice, keyboards, and the like I/Os are within the scopeof various embodiments. In some embodiments, the ASIC 264 defines aninterface between the computer 262 and other components in the cleaningapparatus 200, such as the cleaning modules 220, 230, the stage 240, andthe cleaning substance storage 250. In at least one embodiment, the ASIC264 is a stand-alone controller of at least one component of thecleaning apparatus 200. In at least one embodiment, at least one of thecomputer 262 or the ASIC 264 is omitted from the cleaning apparatus 200,and/or provided outside the housing 210. The described arrangement ofthe controller 260 is an example. Other arrangements are within thescope of various embodiments.

The ventilation device 270 includes a blower 272 and an exhaust piping274. The blower 272 is arranged on the top wall 211 and configured togenerate an air flow through the housing 210 and around the cleaningmodules 220, 230 and the stage 240. The air flow then escapes thehousing 210 via the exhaust piping 274. The air flow keeps the interiorof the housing 210 under pressure and moves contaminants away from thesubstrate being cleaned. In at least one embodiment, the air flowremoves vapor and/or odor of one or more cleaning substances stored inthe cleaning substance storage 250 from the housing 210. In the specificconfiguration shown in FIGS. 2A-2B in accordance with some embodiments,the cleaning modules 220, 230 and the stage 240 are arranged upstream ofthe cleaning substance storage 250, to prevent vapor of the cleaningsubstance(s) from undesirably reaching the cleaning modules 220, 230and/or the substrate to be cleaned. In at least one embodiment, theventilation device 270 is omitted from the cleaning apparatus 200. Thedescribed arrangement of the ventilation device 270 is an example. Otherarrangements are within the scope of various embodiments.

FIG. 3A is a schematic top-front-right perspective view of a cleaningmodule 300, and FIG. 3B is a schematic top-rear-right perspective viewof the cleaning module 300 in accordance with some embodiments. In someembodiments, the cleaning module 300 corresponds to one of the cleaningmodules 220, 230 of the cleaning apparatus 200.

The cleaning module 300 includes a case 310. The case 310 is box-shapedand has a top wall 311, a front wall 312, a rear wall 313, a right wall314, a left wall 315, and a bottom wall 316. At least one of the wallsof the case 310 has a door arranged to permit an operator or equipmentto access one or more components inside the case 310. For example, thefront wall 312 defines a door attached to the left wall 315 by a hinge317. The top wall 311 has an arrangement (not shown) configured toattach the cleaning module 300 to a support, such as the frame or railarrangement 218 described with respect to FIGS. 2A-2B. The describedarrangement of the case 310 is an example. Other arrangements are withinthe scope of various embodiments.

The cleaning module 300 further includes a base member 320 arranged in amiddle of the case 310, between the front wall 312 and the rear wall313. In the specific configuration shown in FIGS. 3A-3B, the base member320 is a board. Other configurations for the base member 320 are withinthe scope of various embodiments.

A front side of the base member 320 is best seen in FIG. 3A. A wipertape supplying reel 322 and a wiper tape collecting reel 324 arerotatably supported on the front side of the base member 320. In thespecific configuration shown in FIG. 3A, the wiper tape supplying reel322 and wiper tape collecting reel 324 are supported to be rotatableabout a common rotational axis. A cleaning head 326 and one or moreguide rollers 328 are also mounted on the front side of the base member320. A wiper tape 330 is guided continuously from the wiper tapesupplying reel 322, through one or more guide rollers 328, around thecleaning head 326, and then to the wiper tape collecting reel 324. Asection of the wiper tape 330 guided around the cleaning head 326 isused to clean a substrate as described herein. A separation member 332,such as a disk, is provided between the wiper tape supplying reel 322and the wiper tape collecting reel 324 to prevent the wiper tape 330which has been used to clean the substrate and collected onto the wipertape collecting reel 324 from soiling the fresh wiper tape 330 on thewiper tape supplying reel 322.

A rear side of the base member 320 is best seen in FIG. 3B. A transversemember 333 is attached to the rear side of the base member 320. Firstsliding members 334 are provided at opposite ends of the transversemember 333. Second sliding members 336, such as raised guides, areprovided on inner surfaces of the right wall 314 and the left wall 315,and are slidably engaged with the corresponding first sliding members334. In some embodiments, the second sliding members 336 include slotsformed in the inner surfaces of the right wall 314 and the left wall315. The slidable engagement between the second sliding members 336 onthe right wall 314 and the left wall 315 of the case 310, and the firstsliding members 334 carried by the base member 320 renders the basemember 320 moveable in the Z direction relative to the case 310. Adriver 338 is attached to the base member 320 and to the case 310 tomove the base member 320 in the Z direction relative to the case 310.Examples of the driver 338 include, but are not limited to, a motor, anair cylinder, and the like actuators. A pressure sensor 340 is alsomounted on the rear side of the base member 320. The describedarrangement of the base member 320 and the components mounted thereon isan example. Other arrangements of various components in the case 310 arewithin the scope of various embodiments.

FIG. 3C is a schematic rear view of some components of the cleaningmodule 300 in accordance with some embodiments. FIG. 3C shows the rearside of the base member 320 on which the pressure sensor 340 is mounted.The base member 320 further support a rotational shaft 342 which definesa support structure for rotatably supporting the wiper tape supplyingreel 322 and the wiper tape collecting reel 324. The rotational shaft342 defines a common rotational axis for the wiper tape collecting reel324 and the wiper tape supplying reel 322. In some embodiments, therotational shaft 342 includes two sections (not shown) each rotatablysupporting a corresponding one of the wiper tape supplying reel 322 andwiper tape collecting reel 324, and the sections of the rotational shaft342 is separated by the separation member 332 mounted therebetween.

A wiper tape feeder 344 is mounted on the base member 320 to drive thewiper tape supplying reel 322 to feed out a length of fresh wiper tape330 for cleaning a substrate as described herein, and/or to drive thewiper tape collecting reel 324 to collect a length of used wiper tape330. In an example configuration, the wiper tape feeder 344 includes atleast one motor. In at least one embodiment, the wiper tape feeder 344includes two motors configured to independently drive the wiper tapesupplying reel 322 and wiper tape collecting reel 324. In at least oneembodiment, a transmission arrangement, e.g., one or more gear wheels,is provided to transmit driving power of the wiper tape feeder 344 to atleast one of the wiper tape supplying reel 322 and wiper tape collectingreel 324.

The cleaning head 326 is rotationally mounted on a rotational shaft 346.The rotational shaft 346 is supported, via a spring 348, by the basemember 320. In the example configuration indicated in FIG. 3C, thespring 348 has a first end 350 connected to a first connecting member352 on which the rotational shaft 346 of the cleaning head 326 isrotationally mounted. A second end 354 of the spring 348 is attached tothe base member 320 and connected to a second connecting member 356. Thepressure sensor 340 has a probe end 358 touching the second connectingmember The pressure sensor 340 is configured to detect a pressure Pexerted by the cleaning head 326 on a substrate 360 to be cleaned by thecleaning head 326. In at least one embodiment, the substrate 360 issupported on a stage, such as the stage 240 as described with respect toFIGS. 2A-2B.

The pressure sensor 340 provides a pressure feedback to a controller,such as the controller 260 as described with respect to FIG. 2A. If thepressure P detected by the pressure sensor 340 is higher than apredetermined threshold or range, the controller 260 causes the cleaninghead 326 and the substrate 360 to be moved away from each other in the Zdirection, to prevent, or at least minimizing a likelihood of, damagesto the substrate 360 due to the high pressure P. If the pressure Pdetected by the pressure sensor 340 is lower than a predeterminedthreshold or range, the controller 260 causes the cleaning head 326 andthe substrate 360 to be moved toward each other in the Z direction, toincrease the cleaning efficiency which is likely insufficient due to thelow pressure P. In at least one embodiment, a relative movement of thecleaning head 326 and the substrate 360 in the Z direction is effectedby the driver 338 which lowers or raises the base member 320 with thecleaning head 326 mounted thereon. In at least one embodiment, arelative movement of the cleaning head 326 and the substrate 360 in theZ direction is effected by a Z-direction movement of the stage 240. Inat least one embodiment, a relative movement of the cleaning head 326and the substrate 360 in the Z direction is effected by both the driver338 and the stage 240. The spring 348 is configured to absorb slightfluctuations in the pressure P without triggering the controller 260 tocause the cleaning head 326 and the substrate 360 to be moved toward toaway from each other. For example, when the cleaning head 326 comes intocontact with a clean area of the substrate 360 and when the cleaninghead 326 comes in to contact with an area with adhesive residue on thesubstrate 360, the pressure P varies slightly and the spring 348 absorbssuch a variation. Examples of pressure sensor 340 include, but are notlimited to, piezoresistive sensor, capacitive sensor, electromagneticsensor, piezoelectric sensor, optical sensor, and potentiometric sensor.The described pressure feedback control is an example. Otherarrangements for pressure feedback control are within the scope ofvarious embodiments.

FIG. 3D is a schematic front view of one or more components of thecleaning module 300 in accordance with some embodiments. FIG. 3D showsthe front side of the base member 320. As described herein with respectto FIG. 3A and as shown in FIG. 3D, the wiper tape 330 is continuouslyguided along a wiper tape path from the wiper tape collecting reel 324,via a number of guide rollers 328, over a portion of the cleaning head326, via a number of further guide rollers 328, and then back to thewiper tape collecting reel 324. The number and/or arrangement of theguide rollers 328 and/or the length and shape of the wiper tape pathshown in FIG. 3D are examples. Other arrangements for guiding the wipertape 330 are within the scope of various embodiments.

In at least one embodiment, the wiper tape 330 includes an absorptive,chemical resistant material with dust trapping capability. Theabsorbency and chemical resistance of the wiper tape 330 permits thewiper tape 330 to carry a cleaning substance, e.g., a solvent, to thesubstrate 360 to remove a material (e.g., adhesive) to be removed, asdescribed herein. The dust trapping capability of the wiper tape 330permits the wiper tape 330 to trap contaminants, such as dust and byproducts of the reaction between the cleaning substance and thematerial. Examples of the wiper tape 330 include, but are not limitedto, wipers which are used for cleaning flat display panels, such as TVsor monitors, or for cleaning other types of glass plates. In someembodiments, the wiper tape 330 includes a band of woven cloth of 75%polyester and 25% nylon, identified as CRW200 Woven Type Wiper availableunder the trademark CRYSTALWIPER®. In some embodiments, the wiper tape330 includes a band of woven or knit cloth including split yarn orfiber, available under the trademark SAVINA®MX. In some embodiments, awidth of the wiper tape 330 is smaller than a width of the substrate360, and the entire surface of the substrate 360 is cleaned by movingthe cleaning module 300 over the substrate 360 in several parallellines. In some embodiments, the width of the wiper tape 330 is equal toor greater than the width of the substrate 360, and the entire surfaceof the substrate 360 is cleaned by moving the cleaning module 300 overthe substrate 360 in a single line.

At least one nozzle is arranged along the wiper tape path and upstreamof the cleaning head 326. In the specific configuration shown in FIG.3D, two nozzles 362, 364 are mounted on the base member 320, upstream ofthe cleaning head 326 and are configured to dispense at least onecleaning substances onto a section of the wiper tape 330 facing thenozzles 362, 364. The section of the wiper tape 330 with the cleaningsubstance dispensed thereon is then fed over the cleaning head 326 toclean the substrate 360 with both chemical action of the cleaningsubstance and mechanical action of the wiper tape 330, as describedherein. To remove adhesive residues from a photomask, example cleaningsubstances include, but are not limited to, Ethanol, HP thinner, andNGC04. The arrangement and/or number of nozzles shown in FIG. 3D areexamples. Other arrangements for supplying at least one cleaningsubstance to material to be removed from the substrate 360 are withinthe scope of various embodiments. For example, in at least oneembodiment, the nozzles 362, 364 are omitted from the cleaning module300, and one or more cleaning substances are directly dispensed on thesubstrate 360.

The cleaning head 326 is rotatable about the rotational shaft 346 (FIG.3C). The rotational shaft 346 is oriented in a direction transverse tothe direction in which the cleaning module 300 is to be moved relativeto the substrate 360. For example, in the specific configuration shownin FIGS. 3C-3D, the rotational shaft 346 is oriented in the X directionwhich is perpendicular to the Z direction in which the cleaning module300 is to be moved relative to the substrate 360. In at least oneembodiment, the cleaning head 326 is rotated by a movement of the wipertape 330 between the wiper tape supplying reel 322 and wiper tapecollecting reel 324. For example, when a length of the wiper tape 330 isfed out from the wiper tape supplying reel 322 and another length of thewiper tape 330 is collected onto the wiper tape collecting reel 324, thecleaning head 326 is caused by the movement of the wiper tape 330 torotate counter-clockwise. In at least one embodiment, a length of thewiper tape 330 is repeatedly fed out from and then wound back onto thewiper tape supplying reel 322, while another length of the wiper tape330 is repeatedly collected onto and then fed back out from the wipertape collecting reel 324. As result the cleaning head 326 is caused torotate back and forth both counter-clockwise and clockwise, as indicatedby arrow R in FIG. 3D. In at least one embodiment, the cleaning head 326is actively driven by a driver, such as a motor (not shown). In at leastone embodiment, the cleaning head 326 is not rotatable.

The cleaning head 326 is configured to bring a section of the wiper tape330 guided over the cleaning head 326 into contact with the substrate360 during a relative movement between the cleaning head 326 and thesubstrate 360. In at least one embodiment, the relative movementincludes both a translational movement T of the substrate 360 relativeto the cleaning head 326 and a rotational movement R of the cleaninghead 326 about the rotational shaft 346 (FIG. 3C). In at least oneembodiment, the relative movement includes either the translationalmovement T or the rotational movement R. In some embodiments, therotational movement R and/or the translational movement T isunidirectional. In some embodiments, the controller 260 selects the typeand/or speed of the relative movement to be performed between thecleaning head 326 and the substrate 360 based on various factors,including, but not limited to, the type, thicknesses and area of thematerial to be removed. For example, for cleaning a lightly soiledregion with a small area and/or thickness of adhesive residues, thecontroller 260 in accordance with some embodiments causes auni-directional translational movement T between the cleaning head 326and the substrate 360, while rotating the cleaning head 326 to clean thesoiled region in a single pass. For cleaning a more heavily soiledregion with a larger area and/or thickness of adhesive residues, thecontroller 260 in accordance with some embodiments causes thetranslational movement T to be performed at a slower speed and therotational movement R of the cleaning head 326 to be performed at ahigher speed to increase the cleaning action of the wiper tape 330 onthe substrate 360. For cleaning a heavily soiled region with an evenlarger area and/or thickness of adhesive residues, the controller 260 inaccordance with some embodiments stops the translational movement T andcauses a bi-directional rotational movement R of the cleaning head 326to be performed to clean one portion of the soiled region at a time.When a portion of the soiled region is cleaned, the controller 260causes a small translational movement T to advance the cleaning head 326to the next portion of the soiled region where the translationalmovement T is again stopped and a bi-directional rotational movement Rof the cleaning head 326 is again performed to clean the next portion.

In some embodiments, the cleaning action is further improved bycontrolling how the cleaning substance is dispensed onto the wiper tape330. In at least one embodiment, a cleaning substance is dispensedcontinuously on the wiper tape 330 during the cleaning operation. In atleast one embodiment, the cleaning substance is dispensed intermittentlyon the wiper tape 330 during the cleaning operation. In at least oneembodiment, for cleaning a heavily soiled region, the amount of thecleaning substance dispensed on the wiper tape 330 is increased, and/orthe cleaning substance dispensed at a higher frequency, and/or multipledifferent cleaning substances are dispensed successively orsimultaneously on the wiper tape 330. In some embodiments, differentcleaning substances are dispensed on the wiper tape 330 in differentpasses of the cleaning head 326 over a soiled region. For example, toclean adhesive residues along the line 107 on the photomask 100 in FIG.1B, a first cleaning substance is dispensed on the wiper tape 330 as thecleaning module 300 is moved in the Y direction along the line 107 inthe first pass. The first cleaning substance reacts with, dissolvesand/or dislodges the adhesive residues from the photomask 100, and themoving wiper tape 330 carries the byproducts of the reaction and/or thedislodged adhesive residues and/or other types of contaminants away fromthe photomask 100. In a second pass, a second cleaning substance isdispensed on the wiper tape 330 as the cleaning module 300 is againmoved in the Y direction along the line 107, to remove contaminantsremaining on the photomask 100 after the first pass. The describedcleaning operation is an example. Other cleaning operations with varioussettings on the type, direction, number and speed of movement and/ortype, amount and dispensing frequency of cleaning substance and/or thelike factors are within the scope of various embodiments.

FIG. 3E is a schematic, top-front-right perspective view of a lowerportion of the cleaning module 300, FIG. 3F is a schematic perspectiveview of a bottom wall 316 of the case 310 of the cleaning module 300,and FIG. 3G is a schematic front view of some components in the lowerportion of the cleaning module 300 in accordance with some embodiments.As shown in FIGS. 3E-3G, the bottom wall 316 of the case 310 has a slot366 corresponding to the cleaning head 326. As best seen in FIG. 3G, thecleaning head 326 has a lower portion 368 over which the wiper tape 330is guided and which projects outside the case 310 through the slot 366to bring the wiper tape 330 into contact with the substrate 360. Thecleaning module 300 further includes a suction device 370 configured togenerate inside the case 310 a negative pressure (compared to thepressure outside the case 310). During a cleaning operation,contaminants C generated by the conductor portion are sucked by thenegative pressure into the case 310 via the slot 366. As a result, thecontaminants C are prevented from re-adhering to the cleaned surface ofthe substrate 360. The contaminants C sucked inside the case 310 arefurther exhausted outside by separate piping. In some embodiments, thesuction device 370 is arranged in the case 310. In some embodiments, thesuction device 370 is arranged outside the case 310 and is coupled tothe interior of the case 310 by a piping 372 to generate the negativepressure in the case 310. In some embodiments, an air flow F, such asthe air flow generated by the ventilation device 270 as described withrespect to FIGS. 2A-2B, flows around the cleaning module 300 and thesubstrate 360 further contributes to the movement of the contaminants Cinto the case 310 via the slot 366 and/or away from the region beingcleaned of the substrate 360. The described arrangement for removingcontaminants from the substrate being cleaned is an example. Otherarrangements for contaminants removal are within the scope of variousembodiments.

FIG. 4 is a schematic top-front-right perspective view of a cleaningmodule 400 in accordance with some embodiments. One difference betweenthe cleaning module 400 and the cleaning module 300 described herein isthat the cleaning module 400 is configured to be rotatable about arotational shaft 401 oriented in the Z direction. In at least oneembodiment, both cleaning modules 220, 230 described with respect toFIGS. 2A-2B are replaced by a single cleaning module 400. In at leastone embodiment, each of the cleaning modules 220, 230 is replaced by onecleaning module 400. In at least one embodiment where the cleaningmodule 400 replaces one or both cleaning modules 220, 230, therotational shaft 401 is coupled to the frame or rail arrangement 218 tosuspend the cleaning module 400 above a substrate to be cleaned held onthe stage 240. The cleaning module 400 is then used to clean asubstrate, such as the photomask 100 as described with respect to FIG.1B in the X direction or the Y direction. For example, the cleaningmodule 400 is moved relative to the photomask 100 in the Y direction toclean the line 107 of adhesive residues. At the junction of the line 107and the next line 108, the cleaning module 400 is rotated about therotational shaft 401 to orient the cleaning head 326 along the next line108 to be cleaned. In at least one embodiment, by using the pivotablecleaning module 400, the number of cleaning modules in a cleaningapparatus is reduced. In at least one embodiment, by using the pivotablecleaning module 400, the cleaning operation is performable in variousdirections other than the X and Y directions, and/or along lines ofdifferent shapes other than straight lines. The described arrangement ofpivotability of the cleaning module 400 is an example. Otherarrangements are within the scope of various embodiments.

FIG. 5 is a schematic top-front-right perspective view of somecomponents of a cleaning module 500 in accordance with some embodiments.One difference between the cleaning module 500 and the cleaning module300 described herein is that, in the cleaning module 500, the wiper tapecollecting reel 324 and the wiper tape supplying reel 322 are arrangedto be rotatable about two corresponding parallel shafts 542, 544. In atleast one embodiment, the operation of the cleaning module 500 issimilar to that of the cleaning module 300. Compared to the arrangementin the cleaning module 300 where the rotational shafts of the wiper tapesupplying reel 322 and wiper tape collecting reel 324 are axiallyaligned, the parallel arrangement of the rotational shafts in thecleaning module 500 occupies a greater area on the base member 320, butprovides easier access to service components of the cleaning module.

FIG. 6 is a schematic rear view of cleaning modules 601, 602 in acleaning apparatus in accordance with some embodiments. In at least oneembodiment, the cleaning modules 601, 602 correspond to one or more ofthe cleaning modules 220, 230, 300, 400 and 500. The cleaning module 601is configured to clean a first surface 611 of the substrate 360, whereasthe cleaning module 602 is configured to clean a second, oppositesurface 612 of the substrate 360 in manners similar to those describedwith respect to the operations of one or more of the cleaning modules220, 230, 300, 400 and 500. In at least one embodiment, both surfaces611, 612 are simultaneously cleaned by the corresponding cleaningmodules 601, 602. As a result, the cleaning speed is increased,especially in situations where both surfaces of a substrate are to becleaned.

FIG. 7 is a schematic rear view of a cleaning module 700 in a cleaningoperation in accordance with some embodiments. In at least oneembodiment, the cleaning module 700 corresponds to any one of thecleaning modules 220, 230, 300, 400 and 500. The cleaning module 700 isconfigured to clean the first surface 611 of the substrate 360, then thesubstrate 360 is flipped as indicated by the arrow 701, so that thesecond surface 612 of the substrate 360 is next cleaned by the cleaningmodule 700. For example, the flipping action is performed by a loaderwhich is configured to load and/or unload substrates to be cleanedand/or cleaned substrates into and/or from the cleaning apparatus.Compared to the arrangement with two cleaning modules described withrespect to FIG. 6, the arrangement in accordance with some embodimentsas shown FIG. 7 is more compact.

FIG. 8 is a schematic block diagram of a cleaning apparatus 800 forcleaning photomasks in accordance with some embodiments. The cleaningapparatus 800 includes a controller 860 coupled with and controlling acleaning module driver 861, a photomask holding stage 862, solventsupplies 863, 864, a cleaning head driver 865, a wiper tape feeder 866,and a suction device 867. The controller 860 is further coupled with andreceives data and/or instruction from an user interface 868, a stresssensor 869, and a camera 870. In at least one embodiment, the controller860 corresponds to the controller 260, the cleaning module driver 861corresponds to the driver 338, the photomask holding stage 862corresponds to the stage 240, the solvent supplies 863, 864 correspondto the cleaning substance storage 250, the cleaning head driver 865corresponds to a motor for actively driving the cleaning head 326 asdescribed herein, the wiper tape feeder 866 corresponds to the wipertape feeder 344, the suction device 867 corresponds to the suctiondevice 370, the user interface 868 corresponds to the touch screen 266and/or other 1/0 described with respect to the controller 260, thestress sensor 869 corresponds to the pressure sensor 340, and the camera870 corresponds to the camera for monitoring cleaning quality asdescribed herein.

FIG. 9 is a flow chart of a method 900 of cleaning a photomask inaccordance with some embodiments. In at least one embodiment, the method900 is performed by the cleaning apparatus 200 and/or at least one ofthe cleaning modules 220, 230, 300, 400, 500, 601, 601, and 700, toclean adhesive residues from the photomask 100 as described herein.

At operation 905, a wiper tape is guided from a supplying reel, over acleaning head, and then onto a collecting reel. For example, the wipertape 330 is guided from the wiper tape supplying reel 322, over thecleaning head 326 and then onto the wiper tape collecting reel 324, asdescribed herein.

At operation 915, a section of the wiper tape over the cleaning head isbrought into contact with an adhesive residue on a surface of aphotomask. For example, a section of the wiper tape 330 over thecleaning head 326 and with a cleaning substance dispensed thereon isbrought into contact with the adhesive residues 104 on the photomask100, as described herein.

At operation 925, a relative movement is generated between the photomaskand the section of the wiper tape to remove the adhesive residue fromthe surface of the photomask. For example, a translational movement Tand/or a rotational movement R is/are generated between the wiper tape330 over the cleaning head 326 and the photomask to remove the adhesiveresidues from the photomask, as described herein. In some embodiments,one or more cleaning substances are dispensed and/or a stress of thecleaning head 326 on the photomask is controlled and/or contaminantsgenerated by the cleaning operation are sucked away, as describedherein.

The above method embodiment shows example operations, but they are notnecessarily required to be performed in the order shown. Operations maybe added, replaced, changed order, and/or eliminated as appropriate, inaccordance with the spirit and scope of embodiments of the disclosure.Embodiments that combine different features and/or different embodimentsare within the scope of the disclosure and will be apparent to those ofordinary skill in the art after reviewing various embodiments.

In some embodiments, by providing a cleaning apparatus and/or a cleaningmodule using a wiper tape, automatic cleaning of a substrate, such as aphotomask is achievable. As a result, manual cleaning of photomasksafter a de-pellicle process is avoidable, saving labor and time forphotomask cleaning while ensuring consistency of cleaning efficiency andquality. Compared to manual photomask cleaning, a cleaning apparatusand/or cleaning module m one or more embodiments provide fixed and/orcontrollable cleaning width and path which result in a lower likelihoodof unremoved adhesive residues remaining on the photomask after thecleaning operation. In some embodiments, the pressure exerted on thephotomask during the cleaning operation is detected and controlled to bein an acceptable range. As a result, damages to the photomask beingcleaned are avoidable, while cleaning performance is improved due to thestable wiping pressure. In some embodiments, contaminants generated bythe cleaning operation are sucked away from the photomask being cleaned.As a result, the cleaning quality is improved because contaminants suchas adhesive residue and/or cleaning substance are unlikely to re-adhereto the cleaned substrate. Some embodiments provide a multi-module and/ormulti-direction and/or multi-solvent cleaning apparatus in which thecleaning operation is controllable by varying one or more factors,including but not limited to, type, direction, number and speed ofrelative movement between the wiper tape and the photomask, as well astype, amount and dispensing frequency of at least one cleaningsubstance. The control flexibility permits the cleaning apparatus to bequickly adapted to various types of substrate to be cleaned and/orvarious types of materials to be removed. A continuous photomaskcleaning process suitable for mass production with high success rate andstable quality is thus provided.

In some embodiments, a cleaning module comprises a support structureconfigured to rotatably support a wiper tape supplying reel and a wipertape collecting reel, a cleaning head, and a suction device. Thecleaning head is configured to, during a cleaning operation, clean asubstrate with a wiper tape which is guided continuously along a wipertape path from the wiper tape supplying reel, around a portion of thecleaning head, and then to the wiper tape collecting reel. The suctiondevice is configured to suck contaminants generated during the cleaningoperation away from the portion of the cleaning head.

In some embodiments, a cleaning apparatus comprises a stage configuredto support thereon a substrate to be cleaned, and at least one cleaningmodule moveable relative to the stage. The at least one cleaning modulecomprises a support structure, a cleaning head, a pressure sensor, and adriver. The support structure is configured to rotatably support a wipertape supplying reel and a wiper tape collecting reel. The cleaning headis configured to, during a cleaning operation, clean the substratesupported on the stage with a wiper tape which is guided continuouslyalong a wiper tape path from the wiper tape supplying reel, around aportion of the cleaning head, and then to the wiper tape collectingreel. The pressure sensor is configured to detect a pressure exerted bythe cleaning head on the substrate. The driver is configured to move thecleaning head in a first direction toward or away from the substrate inresponse to the pressure detected by the pressure sensor.

In a method of cleaning a photomask in accordance with some embodiments,a wiper tape is guided from a wiper tape supplying reel, over a cleaninghead, and then onto a wiper tape collecting reel. A section of the wipertape over the cleaning head is brought into contact with an adhesiveresidue on a surface of the photomask. A relative movement is causedbetween the photomask and the section of the wiper tape to remove theadhesive residue from the surface of the photomask.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A cleaning apparatus, comprising: a stageconfigured to support thereon a substrate to be cleaned; and at leastone cleaning module moveable relative to the stage, the at least onecleaning module comprising: a support structure configured to rotatablysupport a wiper tape supplying reel and a wiper tape collecting reel; acleaning head configured to, during a cleaning operation, clean thesubstrate supported on the stage with a wiper tape which is guidedcontinuously along a wiper tape path from the wiper tape supplying reel,around a portion of the cleaning head, and then to the wiper tapecollecting reel; a pressure sensor configured to detect a pressureexerted by the cleaning head on the substrate; and a driver configuredto move the cleaning head in a first direction toward or away from thesubstrate in response to the pressure detected by the pressure sensor.2. The cleaning apparatus of claim 1, wherein the at least one cleaningmodule is moveable relative to the stage in a second directiontransverse to the first direction.
 3. The cleaning apparatus of claim 1,wherein the at least one cleaning module comprises: a first cleaningmodule moveable relative to the stage in a second direction transverseto the first direction; and a second cleaning module moveable relativeto the stage in a third direction transverse to the first direction. 4.The cleaning apparatus of claim 1, wherein the at least one cleaningmodule is rotatable about an axis oriented in the first direction. 5.The cleaning apparatus of claim 1, wherein the cleaning head isrotatable about a rotational axis oriented perpendicular to the firstdirection, and the at least one cleaning module is moveable relative tothe stage in a second direction perpendicular to both the firstdirection and the rotational axis of the cleaning head.
 6. The cleaningapparatus of claim 1, further comprising: a housing accommodating the atleast one cleaning module and the stage therein; and a ventilationdevice configured to generate an air flow through the housing and aroundthe at least one cleaning module and the stage.
 7. The cleaningapparatus of claim 6, further comprising: at least one cleaningsubstance storage accommodated in the housing, the at least one cleaningsubstance storage configured to supply at least one cleaning substanceto clean the substrate with the wiper tape and the at least one cleaningsubstance at the cleaning head, wherein, in the air flow, the at leastone cleaning module and the stage are arranged upstream of the at leastone cleaning substance storage.
 8. A cleaning apparatus, comprising: asupport structure configured to rotatably support a wiper tape supplyingreel and a wiper tape collecting reel; a cleaning head configured to,during a cleaning operation, clean a substrate supported on a stage witha wiper tape which is guided continuously along a wiper tape path fromthe wiper tape supplying reel, around a portion of the cleaning head,and then to the wiper tape collecting reel; a pressure sensor configuredto detect a pressure exerted by the cleaning head on the substrate; adriver configured to move the cleaning head in a first direction towardor away from the substrate in response to the pressure detected by thepressure sensor; and a suction device configured to remove contaminantsgenerated during the cleaning operation away from the cleaning head, thecleaning head, the wiper tape supplying reel and the wiper tapecollecting reel being disposed on a same side of the substrate as thesuction device.
 9. The cleaning apparatus of claim 8, wherein thecleaning head protrudes through a hole in the support structure.
 10. Thecleaning apparatus of claim 8 further comprising a first guide rollerpositioned in the wiper tape path between the wiper tape supplying reeland the cleaning head.
 11. The cleaning apparatus of claim 10 furthercomprising a second guide roller positioned in the wiper tape pathbetween the cleaning head and the wiper tape collecting reel.
 12. Thecleaning apparatus of claim 8, wherein the suction device is positionedwithin the support structure.
 13. The cleaning apparatus of claim 8,wherein the wiper tape supplying reel and the wiper tape collecting reelrotate about a same axis.
 14. The cleaning apparatus of claim 8, whereinthe wiper tape supplying reel rotates about a first axis, the wiper tapecollecting reel rotates about a second axis, the first axis beingparallel to the second axis.
 15. A cleaning apparatus, comprising: afirst rotational shaft; a first support structure coupled to the firstrotational shaft, the first support structure configured to rotatablysupport a first wiper tape supplying reel and a first wiper tapecollecting reel; a first cleaning head coupled to the first supportstructure, the first wiper tape supplying reel, the first wiper tapecollecting reel, and the first cleaning head configured to, during acleaning operation, guide a first wiper tape continuously along a firstwiper tape path from the first wiper tape supplying reel, around aportion of the first cleaning head, and then to the first wiper tapecollecting reel; a pressure sensor configured to detect a pressureexerted by the first cleaning head; a driver configured to move thefirst cleaning head in response to the pressure detected by the pressuresensor; and a suction device configured to remove contaminants generatedduring the cleaning operation away from the first cleaning head, thefirst cleaning head, the first wiper tape supplying reel and the firstwiper tape collecting reel being disposed on a same side of a substrateas the suction device.
 16. The cleaning apparatus of claim 15 furthercomprising a cleaning substance storage configured to dispense cleaningfluid.
 17. The cleaning apparatus of claim 15 further comprising: asecond rotational shaft on an opposite side of the substrate from thefirst rotational shaft; a second support structure coupled to the secondrotational shaft, the second support structure configured to rotatablysupport a second wiper tape supplying reel and a second wiper tapecollecting reel; and a second cleaning head coupled to the secondsupport structure, the second wiper tape supplying reel, the secondwiper tape collecting reel, and the second cleaning head configured to,during the cleaning operation, guide a second wiper tape continuouslyalong a second wiper tape path from the second wiper tape supplyingreel, around a portion of the second cleaning head, and then to thesecond wiper tape collecting reel.
 18. The cleaning apparatus of claim15 further comprising: a spring via attached to the first cleaning head,the spring configured to partially absorb the pressure exerted by thefirst cleaning head on the substrate.
 19. The cleaning apparatus ofclaim 18, wherein the first cleaning head protrudes through an openingin the first support structure.
 20. The cleaning apparatus of claim 15further comprising: a housing, wherein the first support structure ispositioned within the housing; and a ventilation device attached to thehousing, wherein ventilation is configured to maintain a higher pressurewithin the housing than outside the housing.